Recently, in the medical field, support arm apparatus are being used to support surgeries. For example, a method is proposed in which an observation unit such as a camera for observing an operative site is provided on the front end of an arm section of a support arm apparatus, and the surgeon performs surgery while viewing an image taken by the observation unit. Alternatively, there is also proposed a method of causing a support arm apparatus to perform work that has been done manually in the past, such as by providing a treatment tool such as forceps on a front end of an arm section, and using the treatment tool.
Herein, some support arm apparatus are provided with a motor and a brake in each joint section, and are configured to drive the arm section with the motor. Additionally, when locking the position and the attitude of the arm section, some support arm apparatus are configured to cause the brake to engage while also cutting off the supply of power to the motor. In such a support arm apparatus, when switching from a state in which the position and the attitude of the arm section are locked by the brake to a state in which the brake is released and the arm section is drivable by the motor, there is concern that the arm section could move due to its own weight.
To prevent this, for example, Patent Literature 1 discloses a technology in which, when releasing a brake and resuming a supply of power to a motor, a compensation amount for compensating the falling of the arm section is added to or subtracted from a command value of the current.